Have you ever wondered how many years it would it take to double your money? I am assuming your principal sum is compounded annually in order for this formula to work. I am no genius or expert but I did discover this formula quite accidentally while doing some calculations and I haven't found it in any text book.It is probably there, but I haven't found it.

If you invest any principal amount at 5% it will take 14.20669908 years to double your money. Watch this: ln 2 divided by ln 1.05 =

14.20669908 years. "ln"" mean natural log . Now if you have a calculator you don't have to know anything else about it.

You simply press ln and then 2 and divide by ln 1.05. (You must remember that 5% = .05 and that you have to insert a 1 before it to represent the principal.) Otherwise it won't work.

For example : how many years would it take to double your money ( any sum) if you compounded it at 10% per annum. Answer 7.275 years.

Moving right along: the other day I was at the bank and they were giving me 1.5% over 18 months (simple interest in this case ) on the $50,000 we invested some time ago. I was an absolute idiot to accept it I should have put it into Canadian bank stocks but didn't because I was apprehensive about having enough money for urgent needs in case I had a financial problem - I didn't has it happened.

Now imagine how long it would take to double your money at an annual compounding rate of 1.5% ( forget the complexity of it not being offered or that they offered it as simple interest over 18 months which complicates matters as they really gave us 12/18th of 1.5% which is .06666.% per year ) what a bank !

Now it takes over 46 years to double your money if compounded annually at 1.5%. (46.55552563 years to be more exact

(ln2 /ln1.015 = 46.55552563 years)

EDIT.

To check that 46.5552653 is the doubling time if $1 is invested at a1.5% interest rate compounded annually.

Do this:

On your calculator enter 1.015 to the power of 46.55552563 and you should get 2 or $2.

Enter 1.015 ,then press the y to x key on your calculator and enter the power of 46.55552563 and the answer should be 2.That is the proof of the doubling theory of ln2/ln1.015. And so it is

“ignorance of the fact that man has a wounded nature inclined to evil gives rise to serious errors in the areas of education, politics, social action, and morals” (#407).

Catechism of the Catholic Church.